Marine oil spills can release large volumes of persistently toxic chemicals into the environment, and many large active oil fields are in close proximity to high-density coastal human populations where humans can be exposed through clean-up efforts, through contact with oiled media in popular vacation areas, and through the food chain. Despite the many large oil spills in recent years close to populated regions, and a few studies testing for acute and psychological impacts in humans, remarkably little is known of the medium and long-term health effect, including impacts on important biological processes such as reproduction, development, growth, and performance. The Deepwater Horizon oil spill provides an opportunity to study such effects. The investigators use the Gulf Killifish as a sentinel animal model because they offer an opportunity to carefully link cause with effect by virtue of their relatively short life cycle, a wll-provisioned molecular and physiological toolkit, their local residence and well-documented exposure to the oil spill event in the field, and because they are tractable for laboratory and fied studies providing an opportunity to verify predicted effects in the real world. The aims are to tet for oil spill effects at various sensitive stages of the vertebrate life cycle including effects tht span generations, to characterize the spatial and temporal extent of vertebrate risk from the spill, and to test for the influence of individual and population genetic variation on sensitivity o oil pollution. These data will offer insight into risk and mechanisms of oil spill impacts in a vertebrate model, offer biomarkers predictive or reflective of impaired biological processes, and accelerate the discovery of genetic and physiological risk factors.